Abstract
Fourteen populations of Meloidogyne graminicola were collected from different agroecological regions of India. Morphological and morphometrical comparisons were made for various nematode life stages. Three populations (Hisar, New Delhi, and Samastipur) were different from typical M. graminicola on the basis of the length of eggs; J2 length, a-value, hyaline tail portion; male length, distance up to excretory pore, spicule and gubernaculum lengths; female length and width, stylet length, distance up to excretory pore, EPST (distance of excretory pore from anterior end / stylet length [females]) ratio, and vulval length. Morphological and morphometrical comparison with closely related species M. graminis, M. oryzae, M. salasi, M. triticoryzae, and M. lini clustered these populations into two groups: Anand, Bhubaneswar, Hyderabad, Jammu, Jorhat, Kalyani, Kanpur, Ludhiana, Mandya, Palampur, Vellayani grouped with M. graminicola, M. triticoryzae and M. salasi; whereas, Hisar, New Delhi, Samastipur grouped with M. oryzae and M. graminis. Molecular phylogenetic analysis using internal transcribed spacer (ITS) suggested that in spite of morphological differences, these populations belonged to M. graminicola.
Highlights
Fourteen populations of Meloidogyne graminicola were collected from different agroecological regions of India
For en face views or body sections, J2 and males of M. graminicola fixed in triethanolamine formalin (TAF) were cleared to pure glycerol (Seinhorst, 1966, 1973); the cleared nematodes or males obtained from stained roots were processed further as per procedure described by Hooper (1970) and mounted in glycerin jelly
The distance of excretory pore from the anterior end was maximum (84.0 to 89.2 mm) in J2 of New Delhi, Hyderabad, Samastipur, Hisar, Kalyani, and Jorhat populations
Summary
Fourteen populations of Meloidogyne graminicola were collected from different agroecological regions of India. Morphological and morphometrical comparison with closely related species M. graminis, M. oryzae, M. salasi, M. triticoryzae, and M. lini clustered these populations into two groups: Anand, Bhubaneswar, Hyderabad, Jammu, Jorhat, Kalyani, Kanpur, Ludhiana, Mandya, Palampur, Vellayani grouped with M. graminicola, M. triticoryzae and M. salasi; whereas, Hisar, New Delhi, Samastipur grouped with M. oryzae and M. graminis. Pockets of heavy infestation of rice nurseries and transplanted crop have been noticed in North Indian plains including Jammu (J&K), Punjab, Himachal Pradesh, Haryana, Delhi, and Uttar Pradesh (Gaur et al, 1996; Pankaj et al, 2006; Singh and Singh, 2009). We sought out to determine the intraspecific variations within the Indian populations of M. graminicola isolates from different agroecological zones based on morphological and morphometric characterization. Molecular phylogenetic analysis of some populations using the ITS marker was attempted to substantiate the morphological and morphometrical analysis
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